First Synthesis of Pentasaccharide Glycoform I of the Outer Core Region of the <i>Pseudomonas aeruginosa</i> Lipopolysaccharide

Komarova, Bozhena S.; Tsvetkov, Yury E.; Pier, Gerald B.; Nifantiev, Nikolay E.

doi:10.1021/jo801561p

Cited by 36 publications

(14 citation statements)

References 22 publications

(34 reference statements)

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“…First, disaccharide acceptor 153 was stereoselectively 1,2‐ cis ‐glucosylated with 3,6‐di‐O‐acetylated donor 46 . Then a 6‐O‐benzoylated donor proved its selectivity in coupling with the primary 6‐OH group of trisaccharide acceptor 155 (Scheme ) . Finally, trisaccharide 157 was 1,2‐ cis ‐glucosylated twice, first with 6‐O‐benzoylated donor 43 , then, after deprotection, the tetrasaccharide 159 was 1,2‐ cis ‐glucosylated with 3,6‐di‐O‐acetylated donor 46 …”

Section: Design Of α‐Selective Glycopyranosyl Donors Relying On Remotmentioning

confidence: 99%

“…For instance, we prepared glycoforms I and II of the lipopolisaccharide (LPS) of Pseudomonas aeruginosa according to this strategy. P. aeruginosa is a pathogen associated with worsening the condition of cystic fibrosis patients. Synthetic fragments of the outer core were needed for the investigation of their role in one of the pathways of the host defense against P. aeruginosa and evaluation of its potential for vaccine development.…”

Section: Design Of α‐Selective Glycopyranosyl Donors Relying On Remotmentioning

confidence: 99%

“…Preliminary investigations showed that it is not possible to introduce 1,2‐ cis ‐linked glucoses at earlier steps of the synthesis, since glycosylations at OH‐3 of 4‐O‐glycosylated 2‐azido‐2‐deoxygalactose failed . The task was solved with the use of glucosyl donors bearing one or two remote stereodirecting groups at O‐6 and O‐3 …”

Section: Design Of α‐Selective Glycopyranosyl Donors Relying On Remotmentioning

confidence: 99%

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Design of α-Selective Glycopyranosyl Donors Relying on Remote Anchimeric Assistance

Komarova

Tsvetkov

Nifantiev

2016

The Chemical Record

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102

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Oligosaccharides have a variety of versatile biological effects, but unlike peptides and oligonucleotides, investigation of the roles of oligosaccharides is not easy. Since biosynthesis of oligosaccharides does not comply with direct genetic control, their isolation from natural sources and biotechnological preparation are complicated, due to the heterogeneous composition of raw carbohydrates. Oligosaccharide synthesis is needed for the establishment or confirmation of the structure of natural glycocompounds. Also, synthetically prepared, defined oligosaccharides and their derivatives are becoming increasingly important tools for many biological and immunological research projects. The key step of oligosaccharide synthesis involves glycosylation, a reaction that builds glycosidic bonds. Usually, construction of 1,2-trans-bonds is easy, and therefore, this reaction can even be included into automated syntheses. At this time, installation of the 1,2-cis-bond remains simultaneously frustrating and compelling. In our and other laboratories, a strategy of α-selective (1,2-cis) glycosylation, relying on remote anchimeric assistance with acyl groups, is studied. The state of the art in this work is summarized in this review.

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Section: Design Of α‐Selective Glycopyranosyl Donors Relying On Remotmentioning

confidence: 99%

Section: Design Of α‐Selective Glycopyranosyl Donors Relying On Remotmentioning

confidence: 99%

Section: Design Of α‐Selective Glycopyranosyl Donors Relying On Remotmentioning

confidence: 99%

See 1 more Smart Citation

Design of α-Selective Glycopyranosyl Donors Relying on Remote Anchimeric Assistance

Komarova

Tsvetkov

Nifantiev

2016

The Chemical Record

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102

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“…The glycosylation of 57 with donor 59 having both 3-Oand 6-O-acetyl groups was highly α-selective producing disaccharide 60 (α/β = 8:1) with an excess of the α-anomer (Scheme 10). They applied the remote participation strategy to the synthesis of pentasaccharide originated from the Pseudomonas aeruginosa lipopolysaccharide (19).…”

Section: B the Remote Participation In Glycopyranosylationsmentioning

confidence: 99%

Remote Participation of Protecting Groups at Remote Positions of Donors in Glycosylations

Kim

Suk

2011

TIGG

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Effects of potentially participating groups at remote positions of glycopyranosyl and glycofuranosyl donors on the glycosylation stereochemistry are reviewed. Substantial evidences in favor of the remote participation by protecting groups are presented and also included are a few reports opposed to the remote participation. A. IntroductionT h e p r o t e c t i n g g r o u p s i n t h e o l i g o s a c c h a r i d e synthesis are used to selectively block interfering functions as well as influence the reactivity and stereoselectivity in the glycosylation steps. The anchimeric assistance of a neighboring participating group such as an acyl group at the O-2 position of the glycosyl donor has been one of the most useful strategies for the stereoselective formation of 1,2-trans glycosides (1−5). The carbonyl functionality at the O-2 position of the glycosyl donor can attack an incipient oxonium ion to give a dioxonium ion. Nucleophilic attack by an acceptor to the opposite face of the dioxonium ion provides the 1,2-trans glycoside. When potentially participating groups are located at remote positions other than the O-2 position of glycosyl donors, the existence of the remote participation by the remote protecting groups in the glycosylation step has been controversial. Although numerous examples for glycosylations with glycosyl donors possessing potentially participating groups at remote positions can be found in the literature, most of them do not provide any information on the remote participation by protecting groups in glycosylations. There have been reports both in favor of and opposed to the remote participation by protecting groups in glycosylations. Herein we review the effects of potentially participating protecting groups at remote positions of glycopyranosyl and glycofuranosyl donors on the glycosylation stereochemistry. Further, we present substantial evidence in favor of the remote participation by protecting groups and also include a few reports that are opposed to remote participation.

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“…These contaminants can cause complications in subsequent catalytic debenzylation reactions. 14,15 Thus, the search for reagents and conditions for efficient reduction of carbohydrates or noncarbohydrate azides is an ongoing important task.…”

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confidence: 99%

Water-Dependent Reduction of Carbohydrate Azides by Dithiothreitol

et al. 2013

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First Synthesis of Pentasaccharide Glycoform I of the Outer Core Region of the Pseudomonas aeruginosa Lipopolysaccharide

Cited by 36 publications

References 22 publications

Design of α-Selective Glycopyranosyl Donors Relying on Remote Anchimeric Assistance

Design of α-Selective Glycopyranosyl Donors Relying on Remote Anchimeric Assistance

Remote Participation of Protecting Groups at Remote Positions of Donors in Glycosylations

Water-Dependent Reduction of Carbohydrate Azides by Dithiothreitol

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